NEW YORK: Turmoil in the U.S. housing sector reverberated across the industry Tuesday, reinforcing the mood among investors that the downturn has not yet reached bottom.

Freddie Mac, the big mortgage finance company, posted a $2 billion loss for the third quarter and warned that it might not have enough capital on hand to cover the mandatory reserves for its mortgage commitments. It had a $715 million loss a year earlier.

The company has been battered by a rising wave of foreclosures tied to subprime mortgage defaults and is now “seriously considering” cutting its stock dividend.

Freddie Mac's misfortune is particularly rattling because the company is considered to be protected by an implied government guarantee. The company said that it would seek counsel from Goldman Sachs and Lehman Brothers for its short-term efforts to shore up its reserves.

Shares of the company had plummeted $12.37, or 33 percent, in afternoon trading Tuesday to $25.13, its lowest level in 11 years. Shares of its sister firm, Fannie Mae, had dropped $9.48, or 25 percent, at $28.10.

“Without doubt, 2007 has been an extremely difficult year for the country's housing and credit markets,” Richard Syron, the chairman and chief executive of Freddie Mac, said in a statement.

Syron was not alone in his lament. D. R. Horton, the largest U.S. home builder, reported a $50.1 million loss in its fiscal fourth quarter as the housing downturn pummeled its inventory, good will and land-use contracts. Lower demand and tighter lending standards have cut back the company's business and caused many clients to cancel contracts.

“We expect the housing environment to remain challenging,” said Donald Horton, the company chairman.

The subprime debacle also claimed another high-profile casualty: Mark Ernst, the chairman and chief executive of H&R Block, said Tuesday that he would resign amid the company's exposure to risky loans. Richard Breeden, a former chairman of the U.S. Securities and Exchange Commission, was taking over as chairman while the chief executive slot was being filled temporarily by Alan Bennett, a former top executive at Aetna, the insurance company.

Building data released Tuesday suggested that U.S. housing troubles would only worsen. Groundbreaking permits fell 6.6 percent in October to their lowest level in over 14 years, a sign that builders were cutting back on residential home projects. Permits have slid nearly 25 percent since October 2006, to a seasonally adjusted 1.18 million annual rate, the U.S. Commerce Department said.

New residential construction grew slightly last month, rising 3 percent, to a 1.23 million annual pace. It was the first increase in four months, but the increase came mostly from a 44 percent leap in multifamily homes like condominiums.

Construction of single-family homes dropped again last month, and over all, housing starts remained near the lowest level since the recession of the early 1990s. “With mortgage financing further constrained and inventories of unsold homes quite high, the near- to medium-term outlook for housing starts is not good,” Joshua Shapiro, chief United States economist for MFR, wrote in a research note.